OALib Journal期刊

ISSN: 2333-9721



匹配条件: “Ceramics” ,找到相关结果约1105条。
Synthesis and Electrical Analysis of Ba5GdTi3V7O30 Ceramics  [PDF]
Bana B. Mohanty, Priyadarshini S. Sahoo, Mahapatra P. K. Sahoo, Ram N. P. Choudhary
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.33027
Abstract: A polycrystalline sample of Ba5GdTi3V7O30 was prepared using a mixed oxide method at high temperature (i.e., at 950℃). The formation of single-phase compound with orthorhombic structure at room temperature was confirmed from preliminary X-ray diffraction study. Detailed studies of dielectric properties of Ba5GdTi3V7O30, investigated in a wide frequency range (102 - 106 Hz) at different temperatures (33℃ - 500℃) showed that these properties of the material are strongly dependent on frequency and temperature. The existence a dielectric anomaly suggests that the compound has a transition temperature at ~385℃. The nature of the variation of conductivity and value of activation energy in different regions, calculated from the temperature dependence of ac conductivity (dielectric data) suggest that the conduction process is of mixed type (i.e., ionic-polaronic and space charge generated from the oxygen ion vacancies). The ac conductivity spectrum obeys Jonscher’s universal power law.
Ceramic Tiles Obtained from Clay Mixtures with the Addition of Diverse Metallurgical Wastes  [PDF]
Nancy Quaranta, Marta Caligaris, Miguel Unsen, Hugo López, Gisela Pelozo, Juan Pasquini, Carlos Vieira
Journal of Materials Science and Chemical Engineering (MSCE) , 2014, DOI: 10.4236/msce.2014.22001

The generation of industrial residues is unavoidable, but these materials may be recovered, redirecting them toward new production processes, rather than allocating them to the stream of discards. The aim of this paper is to study the feasibility of utilization of metallurgical wastes as raw material for tiles in the ceramic industry, using the residual materials as aggregates in clay based ceramics. The residues used are: sludge and slag from several metallurgical processes, Ruthner dust and foundry sand. Samples were obtained from mixtures of clay and each waste in various percentages, which were then heat treated. The pieces obtained were characterized using several techniques, with the aim of determining the properties of these materials in relation to the commercial requirements. A high feasibility of reuse of most of these wastes as raw material in the production of ceramic bodies has been established.

Research on the High Strength Glass Ceramics/Mullite Ceramics Composites  [PDF]
Yi Jun Liu, Jian Feng Huang, Xiu Feng Wang, Qiang Yang, Ya Qin Wang, Pei Wen Rao, Qing Gang Wang
New Journal of Glass and Ceramics (NJGC) , 2011, DOI: 10.4236/njgc.2011.12009
Abstract: In order to improve the bending strength of mullite ceramic thin tiles, SiO2-ZnO-Na2O-Y2O3 glass was prepared on the surface of the tiles. The influences of the thermal properties and thermal expansion coefficient of the glass and the sintering temperature on the structure and the property of the composites were investigated by differential thermal analysis (DTA), X-Ray Diffraction (XRD), Raman and scanning electron microscopy (SEM). The bending strength of the composites was measured with an universal testing machine. Results show that the crystallization temperature of the SiO2-ZnO-Na2O-Y2O3 glass is higher than that of SiO2-ZnO-Na2O glass. The corresponding crystallites show more complex structure for the SiO2-ZnO-Na2O-Y2O3 glass. The thermal expansion coefficients of both glasses are lower than the mullite ceramic tiles. The bending strength of the composites after sintering at 1150°C was obviously improved by 10.7% to 106.2 MPa, compared with the mullite ceramic tiles.
Structural Inversion and Behavioural Changes as a Function of Composition in Sr-La-Al-B-Si Based Glasses  [PDF]
Prasanta Kumar Ojha, Sangram K. Rath, Tapas K. Chongdar, Nitin M. Gokhale, Ajit R. Kulkarni
New Journal of Glass and Ceramics (NJGC) , 2011, DOI: 10.4236/njgc.2011.12004
Abstract: A series of glass sealants for solid oxide fuel cell (SOFC) with compositions SrO (x wt %) La2O3 (15 wt %) Al2O3 (15 wt %) B2O3 (40-x wt %) SiO2 (30 wt %) [x = 10, 15, 20, 25 & 30] [SLABS] have been investigated by quantitative Fourier Transform Infrared Spectroscopy (FTIR). Structural findings from FTIR reveal that with increasing substitu-tion of B2O3 by SrO, even though the B2O3/SiO2 ratio decreases, however the Si-O- non-bridging bond content in the matrix is increasing and glass structure is getting more inverted. UV-Vis Diffused Reflectance Spectroscopy (UV-Vis-DRS) of the glass series shows that electrical band gap of glasses decreases in the series from 3.07eV to 2.97eV with increasing substitution from x = 10 to x = 30. Conductivities of the glass samples were measured by AC impedance spectroscopy and found to be increasing from 2.74 × 10-5 Scm-1 to 1.09 × 10-4 Scm-1 with increasing substitution from x =10 to x = 30.
Investigation of Some Structural and Mechanical Properties of Ba0.5CaxSr0.5-xTiO3 Ceramics  [PDF]
Lubna M. Sharaf El-Deen, Mohamed H. Badr, Abdel-Mageed H. Khafagy, Dalia U. Nassar
Crystal Structure Theory and Applications (CSTA) , 2013, DOI: 10.4236/csta.2013.23018

Ba0.5CaxSr0.5-xTiO3 (BCST) ceramics, where x = 0, 0.1, 0.2, 0.3 and 0.4, were prepared by the conventional solid state reaction technique. X-ray diffraction (XRD) analysis confirmed the formation of BST perovskite phase structure besides some calcium oxide peaks for samples with high Ca content, x. Scanning electron microscopy (SEM) results confirmed the XRD results, i.e., as x increased, the average grain size decreased. Energy dispersive X-ray (EDX) analysis verified the increase of the amount of Ca element with increasing of its content. Mechanical properties such as ultrasonic attenuation, longitudinal wave velocity, and longitudinal elastic modulus were studied by an ultrasonic pulse echo technique at 2 MHz frequency. Investigations of ceramic microstructures and mechanical properties showed their dependence on composition. Increasing of Ca content resulted in a decrease in bulk density and ultrasonic attenuation and an increase in porosity, velocity, and modulus. High temperature ultrasonic studies showed, in addition to Curie phase transition, three or more relaxation peaks and its origin was investigated.

Structural Changes by Thermal Treatment up to Glass Obtention of P2O5-Na2O-CaO-SiO2 Compounds with Bioglass Composition Types  [PDF]
Cristina Volzone, Franco Matías Stábile
New Journal of Glass and Ceramics (NJGC) , 2013, DOI: 10.4236/njgc.2013.31009
Abstract: P2O5-Na2O-CaO-SiO2 compounds are the base of certain glass types. Glasses are solids obtained by fast cooling of melted mix of certain compounds. Different compositions give origin to many products with a variety of applications such as: bottles, coatings, windows, tools for chemical industry, laboratory equipment, optics, as bioceramics, etc. The aim of this work was to analyze structural changes of different composition in the P2O5-Na2O-CaO-SiO2 systems thermally treated up to 1250?C, that is to say, before glass formation, by X ray diffraction. Intermediate and final developed phases up to 1100?C thermal treatment in samples were generated as a function of Na2O/CaO (1 and 1.62) and P2O5/Na2O ratios (0, 0.2 and 0.245). High-and low-combeites, calcium and sodium-calcium silicate were found at the highest studied temperature.
New Method for Synthesis of Coatings of Molybdenum, Tungsten, Their Carbides and Composites  [PDF]
Rhushikesh V. Godbole, Mahendra A. More, Anil S. Gupte, Vijay P. Godbole
Open Journal of Synthesis Theory and Applications (OJSTA) , 2013, DOI: 10.4236/ojsta.2013.22010

In this paper we report, for the first time, a new approach for synthesis of high quality faceted microcrystalline coatings of molybdenum (Mo), tungsten (W), their carbides and composites. These studies are carried out using Hot Filament Chemical Vapor Deposition (HF-CVD) method wherein parent materials (Mo and/or W) are taken in the form of wires (~0.5 mmdia) and are heated to a high temperature (TF ~ 1500 - 2000 C), in ambient of oxygen (O2) diluted hydrogen (H2) gas. Due to high filament temperature (TF), a series of pyrolytic reactions take place. Firstly, the gasification of wire material (Mo and/or W) occurs in the form of its oxide. The oxide molecules reach the substrate which is kept underneath the filament assembly. Secondly, molecular hydrogen gets dissociated into atomic hydrogen and subsequently reaches the substrate to react with oxide molecules, finally leading to the precipitation of a pure metal. This method can also be used, in situ, to convert metallic coatings into their carbides and/or composites. The method offers many other attractive features, which can not be rendered by the conventionalCVD/PVDmethods. The results are discussed in terms of temperature induced “Red-ox” reactions.

Ceramicas eletr?nicas do Departamento Engenharia de Materiais - UFSCar
Souza, D. P. F. de;Paulin F°, P. I.;Morelli, M. R.;Kiminami, R. H. G. A;Rodrigues, A. C. M.;
Ceramica , 1999, DOI: 10.1590/S0366-69131999000400005
Abstract: the research lines of the group on electronic ceramics of dema-ufscar and research facilities are presented together with theses, dissertations and the main research results that was done in the last years. a short summary of the nature of the work in progress is also presented.
Pots, Pans, and People: Ceramic Ecology in West Mexico
Eduardo Williams
Papers from the Institute of Archaeology , 1992, DOI: 10.5334/pia.32
Abstract: Little is known about the interrelationship of environment and ceramic specialization, and many questions still remain to be answered, for example: What factors favor or limit the development of ceramic specialization? Why did pottery apparently arise in some places and not in others? One way to answer these questions is to explore the environmental interrelationships of a modern pottery-making community and apply the results to the prehistory of that region
Kadir Sevim,Ayla Canay
Idil Dergisi , 2013, DOI: 10.7816/idil-02-06-05
Abstract: Rug" can be defined briefly as a name given to a kind of woven ground cloth. In various parts of the world, many people from different cultures use all kinds of woven products in their living spaces either for necessity or for decoration purposes. These woven products has a past transferred through generations Despite the changes in production techniques along with changing technology in our day, meaning in the ornaments has come to this day preserving its actual value.The ornaments used in rugs keep on being an inspiration to many artists. In this paper, commitment motive used in rugs will be defined and the ceramic samples made with the influence of this motive will be explained with their images.

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